Correct me if I'm wrong, but I don't think D has the ability to just import C headers and seamlessly use them without having generated or manually written `extern` declarations?
C (or even C++) functions can be called directly from D. There is no need for wrapper functions, argument swizzling, and the C functions do not need to be put into a separate DLL.
I think Walter Bright achieved this via implementing a full-blown C++ parser in the dlang compiler. A [God-Tier] achievement.
Not quite as seamless as Zig, but dstep is an external program that leverages libclang to do the same thing (and generates a D module for you), as well as e.g., smartly convert #define macros to inlineable templates functions :)